Hydraulic drive



May 11, 1965 D. RACICOT I 3,182,455

HYDRAULIC DRIVE Filed Dec. 16, 1963 2 Sheets-Sheet 1 Z73/244-6Z547 0 %Z 7 n I y IN VE N 750/? Donal/b0 RACICOT PAR qauw WW AGENT D. RACICOT HYDRAULIODRIVE May 1 1, 1965 2 Sheets-Sheet 2 Fi led Dec. 16, 1963 8 3% INVEN7UR Da/mf/ien RAK/(C 7' PAR AGENT I mm mw R R .w mh mm mm United States Patent 3,182,455 HYDRAULIC D Donatien Racicot, St. Paul dAbbotsford, Quebec, Canada, assignor of fifty percent to Hector Vincent line, St. Vaiericn, Quebec, Canada Filed Dec. 16, 1963, Ser. No. 331,030 7 Claims. (Cl. 60-53) The present invention relates to a hydraulic drive for driving at a relatively low speed, conveyor belts, chains, and the like.

The hydraulic drive in accordance with the invention has a specific application for driving the chain of a stable cleaning system, although it is not limited to this application.

Various mechanical drives are already known for driving the endless chain of a stable cleaning system at a low speed. The speed reducing and driving units which are normally driven by an electric motor consist of gear trains, pulley and belt drives, ratchet drives, and the like mechanical means.

The devices have been found to wear out very quickly due to the large pull which has to be exerted on the stable cleaning chain, especially when used in large stables, and, moreover, no efficient means have been found to prevent breakage of the chain or of the drive mechanism when obstructions prevent the chain from moving.

This chain stoppage is frequent, especially in wintertime when the refuse or manure freezes in the gutter of the stable cleaning system. In order to try to eliminate the breakage of the system, overload cut-out switches are inserted in the electric circuit of the primary electric motor, in which case the motor has to be re-started manually. In some other systems, the overload cut-out switches are coupled with a time delay resetting switch, which results in repeated starts and stops of the motor and consequent stresses on the drive system, reulting in eventual breakage of the system.

In still other known systems, when obstruction occurs, there is a time delay mechanism allowing the motor to try to start the chain moving during a period of, say, thirty seconds. This might result in an electric motor burn-out or breakage of some elements in the mechanical transmission.

In all cases, excessive stresss are imparted to the chain and to the mechanical drive elements.

Friction clutches, or the like devices, when used in the mechanical system of the drive, have been found to wear out very quickly.

Accordingly, the general object of the present invention relates to the provision of a drive for conveyors and the like and, more specially, for driving the endless chain of a stable cleaning apparatus, which will eliminate the above-noted disadvantages and drawbacks.

A more specific object of the present invention resides in the provision of a hydraulically-operated drive for endless conveyor belts or chains and, more particularly, for conveyor chains of stable cleaning systems, said drive normally moving the chain or other conveyor elements at a low speed and exerting on the conveyor element a constant driving force, even if the said conveyor element is subjected to an obstruction which prevents its moving or start, said drive capable of exerting said force indefinitely without breakage of any parts.

Another object of the present invention resides in the provision of a hydraulic drive or" the character described, which is of very simple construction and which forms a complete assembled unit, and in which the speed of rotation can easily be adjusted by controlling the flow and pressure of the hydraulic fluid.

Another object of the invention resides in the provision of a hydraulic drive of the character described, in

"ice

which at least three hydraulic cylinder and piston units are pivotally mounted and connected to a crank arm secured to the driving shaft and in which the pivots of said units serve as fluid inlet and outlet for the cylinders, whereby the tubing or hosing for the hydraulic circuit is not subjected to any bending movement.

The foregoing and other important objects of the pres ent invention will become more apparent during the following disclosure and by referring to the drawings, in which:

FIGURE 1 is a side elevation of the hydraulic drive in accordance with the invention;

FIGURE 2 is a plan section taken along line 2-2 of FIGURE 1;

FIGURE 3 is a side elevation, on an enlarged scale, of one cylinder and piston unit, partly shown in longitudinal section;

FIGURE 4 is a longitudinal section of the rotary valve;

FIGURE 5 is a longitudinal section of the rotor of the rotary valve;

FIGURE 6 is a plan section taken along line 66 of FIGURE 4; and

FIGURE 7 is a plan section taken along line 7-7 of FIGURE 4.

Referring now more particularly to the drawings in Which like reference characters indicate like elements throughout, the hydraulic drive in accordance with the invention comprises a base 1 in the form of an elongated metal channel resting on and slidably fitting over a support beam 2.

A shelf 3 is supported by the inner end portion of channel 1 by means of upstanding legs 4. Shelf 3 supports an electric motor 5, a hydraulic fluid tank 6 and a hydraulic pump '7, driven in rotation by motor 5 through motor shaft 8, pump shaft 9, and flexible coupling it A sleeve 11 is mounted on top of and is secured to the outer portion of the channel-shaped base 1 and serves as a housing for a drive shaft 12, which is rotatably mounted in sleeve 11 by means of thrust bearings 13 and 13', the latter being inserted in sleeve 11 and secured thereto by bolt-s 16.

Drive shaft 12 is mounted substantially perpendicular to base 1 and freely extends through said base. A plate member 15 having a star shape providing three equally angularly spaced radially protecting arms 15 is secured at its center to the top of sleeve 11 by welding or the like, and one arm is aligned with and overlies channelshaped base 1, being secured thereto at its inner end by means of support leg 17.

A second plate-like member 18, having the same shape as plate member 15, is spacedly disposed over the same with its arms 18' in alignment with arms 15', being secured to the first plate 15 and supported thereby by means of three pairs of spacer rods 19 connecting the arms of the two plate members.

A rotary valve assembly 20, the description of which will be given hereinafter, is mounted on the top plate 18 with its rotor co-axial with the drive shaft 12.

The rotor of valve 20 has a crank arm 21, the outer end of which is connected to the outer end of a crank arm 22, which is secured to drive shaft 12, by means of a wrist pin 23.

Three hydraulic cylinder and piston units 25 are mounted for pivotal movement between the two plate members 15 and 18. Each unit 26 comprises a cylinder 24 and a piston rod 25, the free end of which is pivotally connected to wrist pin 23.

Each cylinder 24 is provided intermediate its ends with aligned upper and lower pivot members, disposed between the spacer rods 19 of each pair and pivotally supporting units 26. Said pivot members consist of upper and lower stud shafts 2'7 and 28 secured to cylinder 24 and of upper and lower pivot blocks 29 and 3% secured to top and bottom plate members 13 and 1,5. The stud shafts rotatably' engage the bore of the respective pivot blocks.

Upper stud shaft 27 is hollow, being in the form of a tube, in communication through opening 31 with the inside 7 of cylinder 24. Said tube is inwardly threaded for receiving a coupling 32 passing through the bored upperpivot block 39 and through the top plate member 13, said coupling being connected to flexible tubing 33 for the transmission of hydraulic fluid and return thereof to and from cylinder 24.

The tubing 33 of each cylinder unit is connected to a port made in the housing of rotary valve 26. Fluid under pressure is transmitted from the outlet port of pump 7 to the rotary valve 26 by flexible tubing 34,-while the fluid is returned from thevalve through flexible tubing 35 to the.

tank 6.

The free end of the drive shaft 12 is splined, as shown at 36, to receive a sprocket gear, not shown, which is in meshing arrangement with the chain (not shown) of a stable cleaning system. However, it is obvious that the shaft could be provided with any type of gear or pulley means for driving other conveyor systems.

The entire drive assembly is displaceable in adjusted manner along beam 2, in order to confer the desired tautness to the conveyor chain. For this purpose, an eye bolt 37 has its eye portion secured to beam 2 by means of bolt 38 passing through a longitudinal slot 38mad'e in the channel-shaped base 1.

The threaded end ofeye bolt 37 passes through a hole of leg 4 and receives the nut 39. By screwing nut 39, the

7 whole drive assembly is displaced outwardly from the outer end of beam 2, to thereby tightenthe conveyor chain.

The three cylinder. and piston units 26 are angularly spaced 120 apart and are pivotable in a plane parallel to the top and bottom plates 18 and 15 and their piston rods 25 are adapted to rotate crank arms 21 and 22 of the rotary valve 263 and of the drive shaft12. Each cylinder 24 consists of a cylindrical housing having a welded closure disc dtiat one end and externally threaded to receive a header sleeve 41, having its inwardly protruding internal cylindrical surface 41' provided with three annular grooves, one receiving a graphite wiper ring 42 and the other two' each receiving an O-ring 33 and back-up washer 44. An O-ring 45 seals the threaded connection between the header sleeve 41 and the cylinder proper.

The piston rod consists essentially of a cylindrical mem ber 45 welded to a disc-like cap 47 at its innerend and to an apertured coupling member '48 at its outer end. A

ring member 48' surrounds wrist pin 23 and has a sleeve in which member 48 is inserted and connected by means of a bolt passing through said sleeve and the aperture of said member 43.

Member 46 has a sliding fit with the inner cylindrical surface 41' of the header sleeve 41 and is spaced inwardly from the cylinder 24 which defines an annular space therewith.- Cap 47 protrudes radially outwardly from memberdo and abuts against shoulder 49 of header sleeve 41 in the extended limit position of the piston rod.

This cylinder and piston unit is a single-acting hydraulic unit and the hydraulic fluid is fed to and is returned from the cylinder through the single communication constituted Crank arm 21 has a collar 58 fitted over the outer end of the coupling member 56 and secured thereto by a set screw 5d. The coupling member 56 has a portion over? FIG. 1) to thereby fixthe valve body 50 in lying and having a sliding fit with the bottom end-face 60 of the body 50. N

The upper end of the rotor is inwardly threaded at 61 for receiving a cap 62, screwed therein and overlying the top end face 63 of body 5% Thus, cap 62 and coupling member 55 positively maintain the rotor in a predetermined longitudinal position within the body 59, while allowing free rotation thereof by means of crank'arm 21.

A'bracket d4 is reniovably secured to thebottom face of the body 5% by means of bolts 65 :and serves to secure the rotary valve 26 onthe top plate member 18 of the drive assembly, in a position. with the rotor 51 coaxial with the drive shaft 12. Bracket 64 provides a circular flange 64' retained by overlapping fasteners 64" (see angularly ad- 'usted position ontopplate 18. r

The lower feeding section 53 ofthe bore of the rotor 51 is provided with a lateral elongated opening 66, ex tending through a little lessthan 180. An annular groove 6% is made on the outside surface of rotor 51' below opening 66 and is in communication with the inside of the rotor through hole 70. V

The upper return section 52 of the rotor 51 is similarly provided with a lateral elongated opening 71, which is diametrically opposed to opening 66 and which also extends through a little less than 180. Below the return opening 71, the rotor 51 'isprovided with an annular groove 74 in communication with the interior. of the section 52 by a hole 75. I

The body 5%? is provided with spaced annular narrow grooves 76' for receiving O-rings 77 which" are disposed aboveopening .71 and below groove .69. Additional O-rings 77 at both ends of rotor 51'seal the connections of the latter with member 56 and cap 62.

Groove 69 and its hole 79 are in alignment with'afeeding port 78, whilegroove 74- and hole'75 are in alignment with return port 79. Q

, A longitudinal threaded bore 84 is made in the body 5d of the valve and establishes communication between the two ports 73 and 79 to form a by-pass, in which is 10-- cated a pressure release valve formed by a valve seat 81, a ball 82, a coil spring 83, and a screw plug 66. V

Bore 86 opens at the top end: face 63 of the valve body 5! for inserting and removing'the valve arrangement, said bore being closed by plug 86.

Each cylinder and piston unit 26 of the drive assembly is connected to a related pair of feeding and return openings made in the feeding'section 53 and return section 52 of rotor 51, by means of a cylinder. port87 made in the body of the rotary valve. As there are three cylinder and piston units 26, consequently therezwill beithree cylinder ports87, which are equally an gularly spaced at apart in the body wet the rotary valve.

Each cylinder port 87 has a feeding branch 88 at the level of the corresponding rotor feeding opening 66. Each cylinder port 87 has, furthermore, a return branch 89, standing vertically withinthe body of the valve and opening at the level of return opening 71, in the vertical plane containing branch 88.-

The system in accordance with the invention operates as follows:

. Upon starting electric motor 5, pump 7 is rotated and delivers hydraulic fluid under pressure through the rotary valve intake port 73' and the fluid under pressure enters the feeding section 53 of rotor-51 through groove wand hole 70. The fluid under pressure leavesthe rotor 51 through feeding opening 66, and the valve body through the cylinder port or ports 87 momentarily in communication With feeding opening 6-6. Thus, the cylinder unit connected with cylinder port '87'exerts a pushing stroke on the crank arm, 22 of the drive shaftlZ, whereby starting rotation of the latter. Said drive shaft 12 in turn rotates the crank arm 21. of rotary valve 20, whereby the rotor 51 is caused to rotate in the same direction of rotation :as the drive shaft 12.

When the system is stationary, there is always at least one cylinder port 87 having its feeding branch 88 in communication with .the feeding section of the rotor, while the return branches 89 of the remaining cylinder ports 87 are in communication with the return section 52 of the rotor 51. Thus, upon starting, at least one cylinder is caused to exert an active stroke while the two other cylinders return their fluid back through the return section of the rotary valve. Due to the act-ion of the active cylinder, the fluid is returned through the return branches 89 through the same hosing connected to the cylinders being emptied of fluid through the return section openings 71 and back into the tank 6 and intake of the pump 7.

Upon rotation of the rotor 51, the feeding opening of said rotor successively comes in communication with the three angularly spaced feeding branches 88 of the cylinder ports 87, thereby causing an active stroke of the three cylinder units in succession at each 120 rotation of rotor 51. Feeding opening 66 and return opening 71, each extend through 180 less the diameter of feeding or return branches 88, 89. Thus, each cylinder receives pressure fluid for 180 of rotor rotation and returns the fluid for the remaining 180 of rotor rotation.

There is continuous rotation of the drive shaft under the successive actions of the three cylinder units, and the admission and return of pressure fluid to the three cylinder units is perfectly synchronized due to the fact that this valve rotor is directly connected by crank arm 21 to the crank arm 22 of the drive shaft.

The drive shaft is rotated at a relatively low speed, which is dependent on the torque produced on the drive shaft and the flow and pressure of the fluid delivered to the cylinders by the pump.

If there are any obstructions preventing movement of the conveyor driven by shaft 12, thereby preventing proper functioning of the cylinder units, by-pass valve 82 simply opens at a calibrated overload pressure and the pressure fluid entering intake port 78 passes directly through the by-pass valve 80, 81 into the return port 79 and back into the tank 6. However, during this return, pressure continues to be exerted by the cylinder units on the drive shaft until the obstruction is either overcome or the electric motor is stopped. However, the pump 7 can continue to operate indefinitely without any wear and tear on the drive mechanism or breakdown of the conveyor chain, because the by-pass valve opening pressure can be set at the exact proper value.

The hosing connecting the cylinder units to the rotary valve 20 and the latter to the pump 7 are preferably made of rubber or other elastic material and, therefore, act as shock absorbers in the event of sudden pressure changes within said hosing.

As shown in FIGURE 1, it is a simple matter to adjust the angular position of the valve body 50 with respect to the cylinder arrangement, whereby the drive can be made to rotate clockwise or anticlockwise, depending on the particular application.

Referring to FIGURE 4, it will be seen that the feeding and return openings in the rotor 51, which are disposed at 180 apart, define an aperture less portion of the rotor having a width corresponding to the diameter of the cylinder port, such that for any given cylinder when feeding with pressure fluid is stopped, the cylinder is immediately connected to the return circuit of the fluid.

It is noted that the feeding and return hosing for the cylinders are connected to said cylinders at the pivotal axis thereof, thereby resulting in a minimum of bending of the hosing.

While a preferred embodiment in accordance with the present invention has been illustrated and described, it is understood that various modifications may be resorted to without departing from the spirit and scope of the appended claims.

What I claim is:

1. A hydraulic drive for driving an endless conveyor, comprising a base frame including two spaced support members rigidly interconnected, a drive shaft extending through one of said support members, a crank arm secured to one end of said drive shaft and disposed between said support members, at least three pivot members mounted between said support members and equally angularly spaced with respect to the axis of said drive shaft, at least three single acting hydraulic cylinder and piston units disposed between said support members, having their piston pivotally connected to said crank arm and their cylinders supported by said pivot members, whereby said units are capable of driving said crank arm and drive shaft, a continuously rotatable valve having a body secured on the other one of said support members and a rotor mounted co-axially with said drive shaft, a second crank arm secured to said rotor and pivotally connected at its outer end to said first crank arm, whereby said rotor is rotated by said drive shaft through said second crank arm, a source of pressure fluid, separate feeding and return tubing connecting said valve to said source, a single feeding and return hosing connecting each cylinder to said valve, said valve having fluid passageways made in said body and rotor for the successive feeding and return of fluid to and from said cylinders and a pressure release by-pass connected to the said feeding and return tubing.

'2. A hydraulic drive as claimed in claim 1, wherein said pivot members include two stud shafts secured to the associated cylinder in diametrically opposed relationship and pivot blocks mounted on said support members and engageable with said stud shafts, one of said stud shafts being hollow and in communication with the interior of the associated cylinder through an opening, the associated feeding and return hosing being connected with said hollow stud shaft, whereby said pivot members serve for the feeding and return of fluid to the associated cylinder, as well as pivotal mounting for the cylinder.

3. A hydraulic drive as claimed in claim 1, wherein said source of pressure fluid includes a hydraulic pump driven by a prime motor, said pump and prime motor being mounted on said base frame.

4. A hydraulic drive as claimed in claim 1, wherein said base frame includes a channel member over which said two support members are spa-cedly disposed and to which they are rigidly secured, a beam member over which said channel member is slidably fitted, said beam member supporting the whole assembly, and means connected to said beam member and to said base frame for longitudinally displacing said assembly with respect to said beam member.

5. A hydraulic drive as claimed in claim 1, further including a support beam and wherein said base frame includes a channel member supported in slidable engagement with said sopport beam, with one end protruding from said beam, said drive shaft passing through said one end of said channel member, a sleeve secured on top of said channel member and through which said drive shaft extends, said spaced support members being secured in superposed relationship to said sleeve and to said channel member.

6. A hydraulic drive as claimed in claim 5, wherein said pressure fluid source consists of a hydraulic pump and an electric motor driving said pump, said pump and motor mounted on the inner end of said channel member.

7. A hydraulic drive as claimed in claim 6, further including means for adjustably securing said channel member on said beam longitudinally of the latter.

No references cited.

JULIUS E. WEST, Primary Examiner.

EDGAR W. GEOGHEGAN, Examiner. 

1. A HYDRAULIC DRIVE FOR DRIVING AN ENDLESS CONVEYOR COMPRISING A BASE FRAME INCLUDING TWO SPACED SUPPORT MEMBERS RIGIDLY INTERCONNECTED, A DRIVE SHAFT EXTENDING THROUGH ONE OF SAID SUPPORT MEMBERS, A CRANK ARM SECURED TO ONE END OF SAID DRIVE SHAFT AND DISPOSED BETWEEN SAID SUPPORT MEMBERS, AT LEAST THREE PIVOT MEMBERS MOUNTED BETWEEN SAID SUPPORT MEMBERS AND EQUALLY ANGULARLY SPACED WITH RESPECT TO THE AXIS OF SAID DRIVE SHAFT, AT LEAST THREE SINGLE ACTING HYDRAULIC CYLINDER AND PISTON UNITS DISPOSED BETWEEN SAID SUPPORT MEMBERS, HAVING THEIR PISTON PIVOTALLY CONNECTED TO SAID CRANK ARM AND THEIR CYLINDERS SUPPORTED BY SAID PIVOT MEMBERS, WHEREBY SAID UNITS ARE CAPABLE OF DRIVING SAID CRANK ARM AND DRIVE SHAFT, A CONTINUOUSLY ROTATABLE VALVE HAVING A BODY SECURED ON THE OTHER ONE OF SAID SUPPORT MEMBERS AND A ROTOR MOUNTED CO-AXIALLY WITH SAID DRIVE SHAFT, A SECOND CRANK ARM SECURED TO SAID ROTOR AND PIVOTALLY CONNECTED AT ITS OUTER END OF SAID FRIST CRANK ARM, WHEREBY SAID ROTOR IS ROTATED BY SAID DRIVE SHAFT THROUGH SAID SECOND CRANK ARM, A SOURCE OF PRESSURE FLUID, SEPARATE FEEDING AND RETURN TUBING CONNECTING SAID VALVE TO SAID SOURCE, A SINGLE FEEDING AND RETURN HOSING CONNECTING EACH CYLINDER TO SAID VALVE, SAID VALVE HAVING FLUID PASSAGEWAYS MADE IN SAID BODY AND ROTOR FOR THE SUCCESSIVE FEEDING AND RETURN OF FLUID TO AND FROM SAID CYLINDERS AND A PRESSURE RELEASE BY-PASS CONNECTED TO THE SAID FEEDING AND RETURN TUBING. 